Isomerization processes generally require the removal, e.g., by hydrotreating, of sulfur and nitrogen compounds that can rapidly deactivate or poison the isomerization process catalyst. Consequently, feeds to be isomerized are first contacted with a sulfur tolerant catalyst in the presence of hydrogen to minimize the amount of sulfur in the feed.
Additionally, isomerization processes, particularly those carried out on Fischer-Tropsch derived feed stocks in the presence of hydrogen, are effected with unsulfided catalysts. As a consequence, hydrogenolysis, e.g., hydrocracking, occurs in the processing and produces significant amounts of gaseous products, e.g., methane or C.sub.1 -C.sub.4 hydrocarbons. A process, therefore, that can eliminate or substantially reduce the hydrogenolysis aspect of the process, even in the presence of sulfur, can be more efficient and more economic because of increased yields of desired products and decreased yields of gaseous products.
Natural gas fields typically contain a significant amount of C.sub.5 + material, which is liquid at ambient conditions. These liquids must be upgraded (e.g., sulfur removed) if they are to be used as liquid petroleum fuels. An integrated process, which can upgrade both the natural gas field condensate and the Fischer-Tropsch liquids into high valued liquid petroleum products in a single unit, would be advantageous.
Currently, the gas field condensate is separated from the gaseous product and upgraded in separate vessels to remove sulfur and other undesirable materials in conventional hydrotreating units or in Merox units.